Sao, a moon of Neptune
13,931,115 miles
27 miles
Sao is a moon of Neptune. It has a diameter of 44 kilometres (27 miles). It orbits at an average distance of 22.4 million kilometres (13.9 million miles) from Neptune, taking 2,914 Earth days to complete a full journey around the planet. It is the eleventh moon in distance from Neptune.
Sao was discovered on 14th August 2002 by teams of astronomers led by Matthew Holman and John Kavelaars. Their discovery was as part of a project to search for distant moons of Neptune. In the summer of 2001, they obtained images of areas around Neptune where moons may be located using the Cerro Tololo Inter-American Observatory and Canada-France-Hawaii Telescope. They detected six potential objects, and repeated the search again in August 2002 and August 2003, to confirm their findings. Five of those six new moons were seen again, including the moon that is now known as Sao. The other moons discovered through this method are Halimede, Laomedeia, Psamathe and Neso.
Sao is classed as an irregular prograde moon. An irregular moon usually refers to a moon that has been captured by a planet's gravity rather than one which formed around it. Sao is also an irregular shape. A prograde moon is one that orbits in the same direction as its host planet's rotation. It's likely that Sao was originally an asteroid or an object that formed in the Kuiper Belt.
In Greek mythology, Sao is one of the Nereids, one of 50 daughters of Nereus and Doris. The Nereids are kind and helpful sea nymphs. Sao is seen as the Nereid who would ensure safe passage for sailors in stormy seas, or the rescue of them.
The moon's name was announced on 3rd February 2007. Its provisional name was S/2002 N 2. It may also be referred to as Neptune XI.
